4.3.4
Data Transfer Speed—60 GB model
100
Buffer-Host (maximum)
19.5
Sustained (read Typical)
24.6
Instantaneous (Typical)
Disk-Buffer Transfer (Zone 17)
40.8
Sustained (read Typical)
48.0
Instantaneous (Typical)
Disk-Buffer Transfer (Zone 0)
Mb/s
Description
Figure 11. Data Transfer Speed
y
Instantaneous Disk-Buffer Transfer Rate (Mbyte/sec) is derived by:
(Number of Sectors on a track) * 512 * (Revolution/sec)
Note: Number of sectors per track will vary because of the linear density recording.
y
Sustained Disk-Buffer Transfer Rate (Mbyte/sec) is defined by considering head/cylinder change time
for read operation. This gives a local average data transfer rate. It is derived by:
(Sustained Transfer Rate) = A/(B + C + D)
A = (Number of Data Sectors per Cylinder) * 512
B = (# of Surface per cylinder) - 1) * (Head Switch Time)
C = (Cylinder Change Time)
D = (# of Surface) * (One Revolution Time)
y
Instantaneous Buffer-Host Transfer Rate (Mbyte/sec) defines the maximum data transfer rate on AT
Bus. It also depends on the speed of the host.
The measurement method is given in section 4.3.6 "Throughput" on page 13.
4.3.5
Buffering Operation (Look ahead/Write cache)
To improve the total performance, the file utilizes a ring buffer for look ahead and write cache. The total
of 1916 KB of the buffer is divided into multiple segmented blocks for write buffer or read buffer use.
4.3.6 Throughput
4.3.6.1 Simple sequential access
The following figure illustrates the case of 3-disk Disk Enclosure.
0.96
0.92
Sequential Read (Zone 17)
0.47
0.44
Sequential Read (Zone 0)
Maximum
(second)
Typical
(second)
Operation
Figure 12. Simple sequential access performance
The above table gives the time required to read/write for a total of 8000h consecutive blocks
(16,777,216 bytes) accessed by 128 read commands. The Typical and Maximum values are given by
105% and 110% of T respectively throughout following performance description.
Note: It is assumed that a host system responds instantaneously and that the host data transfer is faster
than the sustained data rate.
Deskstar 60 GXP Hard disk drive specification
13
Содержание IC35L020 - Deskstar 20 GB Hard Drive
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